Governor



June 26, 1945. A. KALIN 2,379,304

GOVERNOR Original Filed March 26', 1941 INCREASES POWER. IN PUT ODEcRmsa's \j POWE R. I N PUT O 46 I l 5 I E I 9 INVENTOR- 3 F'G aABLYBERT KAUN Patented June 26, 1945 GOVERNOR Albert Kalin, Cleveland,Ohio Original application March. 26, 1941, Serial No.

385,228, now Patent No.

1941, Serial No. 403,805

lclaim. This application is a division of my application Serial No.385,228, filed March 26, 1941, Since issued as Patent No. 2,324,514,dated July 20, 1943. The invention relates to certain improvements inand in combination with governors of the type using a fluid pressureoperated servo-motor for regulating, for instance, speed of a primemover or other machine or apparatus to be governed.

A specific problem solved by the instant invention is in connection withregulating the speed of Diesel engines. When the throttle (fuel injectorrack controlling mechanism) is adjusted automatically by a hydraulicservo-motor controlled by engine-speed-responsive means including apilot valve the usual tendency, upon starting up of the engine, is forthe servo-motor to move the throttle rapidly to fully open position.Therefore during starting there is a tendency on part of an engine sogoverned to overspeed or race as it passes through normal speed duringthe starting period. This tendency 'can be obviated by causing theinjectors to be stopped at part fuel Setting until full speed isreached, at which point fuel restraint is removed and the engine madeimmediately able to carry full load if neceessary. The above indicatesone object hereof.

Another object of the present invention is to provide a hydraulicallyactuated governor having means acting temporarily to restrain theinitial movement of the regulating servo-motor to less than its fullstroke at commencement of operation of the governor.

Another object is to provide a speed governor wherein speed responsivemeans and a regulating servo-motor of the governor cooperate during theinitial or starting operation of a governed prime mover to restrainservo-motor operation to less than a full stroke thereof in onedirection until the prime mover is running in a normal manner -that isindependently of extraneous starting force.

In engine-generator units certain adjustments in respect to thegenerator should be efiected during starting and/or initial accelerationof the engine and others not effected until the engine has attainedrunning speed. For example the generator should not be loaded untilsubstantially normal running speed is attained. In case of an electricgenerator it is desirable to force energization of the generator fieldcoils during acceleration and to cease forcing energization thereofafter the engine has attained predetermined running speed.

Another object is to provide, in a governor for prime movers, means toperform appropriate ad- 2,324,514, dated July Divided and thisapplication July 24,

justments during starting of the prime mover and/or when the same beginsto run independently of starting force.

Other objects will become apparent from the following description.

In the drawing Fig. 1 is a schematic assembly view of a governorsubstantially according to my Patent 2,219,229, issued October 22, 1940,incorporating the present improvement in one form including an electriccurrent controlling means; Fig. 2 is a relatively enlarged detailsectional view of the servo-motor restraining mechanism and a differentelectrical circuit which may be controlled by said mechanism, theelements of the servo-motor and said mechanism being shown in a relativeposition different from that shown in Fig. 1.

The principal parts of the illustrative governor mechanism are indicatedby letters; the special subject matter hereof by numerals.

Referring 'to the general arrangement of governor elements, a gear pumpA is shown with a well known check valve system and ducts arranged toenable the pump to draw hydraulic fluid from a sump S and deliver it toan accumulator B having a spring loaded plunger C and, discharge vent Dwhich cooperate to keep the pressure in the accumulator at constantpositive value. The pump is suitably connected to the engine or othermachine to be governed. Fluid from the accumulator is supplied to agovernor port E and continuously therebeyond to one face F of a doubleacting hydraulic servo-motor power piston G. 1 The port E is controlledby a lower land portion of a pilot valve plunger H which, it moveddownwardly from the normal position in which shown, opens the port E toa duct I leading to the opposite (effectively larger) face J of thepower piston, causing upward movement of the piston. Upward movement ofthe pilot valve plunger from its normal position causes an upper landportion thereof to open the duct I at a port K, dumping pressure fluidfrom below the power piston into the sump and causing the piston todescend by reason of the constant pressure maintained at the piston faceF.

The p lot valve plunger H is moved vertically in opposite directions asa result of the difference between centrifugal force on a set offly-balls L rotated by the prime mover and opposing force exerted by anadjustable speeder spring M, so that an increase in speed on part of theprime mover raises the pilot valve plunger and a decrease in speedlowers said plunger. Regulation of speed ,by the servo-motor incident tochange in load is initiated by such movement of the pilot ,valve plungerH.

Power input to the governed prime mover is increased by raising creasedby lowering An arrangement such as thus far described requiresstabilization in order to prevent vacillation in speed or huntingconsequent upon load change and subsequent speed-correcting operation ofthe governor. The stabilizing mechanism includes a hydrauliccompensation system supplied with fluid from the sump and actuating andreceiving compensation pistons of said system operating as a function ofregulating movement of the servomotor piston G to damp or check eachmovement of said piston and prevent temporary overregulation of theprime mover thereby.

The actuating compensation piston N works in a trunk portion of thepower piston G and displaces hydraulic fluid in a duct 0 leading to thereceiving compensating piston P, slidably mounted in a cylindricalextension of the outer pilot valve element, whenever the power piston Gstarts to perform a'regulating operation in either direction. The spaceabove the trunk portion of the power piston is open to the sump throughan upper wall portion of the power cylinder block. The motion of thereceiving compensation piston P is always opposite theregulation-initiating movement of the pilot valve plunger H, and placestemporary primary yielding compensating restraint on each movement ofsaid valve plunger through the intermediary of a coil spring Qconnecting the compensating piston P and valve plunger H. The primarycompensating force is removed, after regulation is effected, byrelieving the positive or negative pressure in the duct 0 through anadjustable secondary compensation leak-off needle valve R communicatingthe duct'O with the sump.

As fully explained in my Patent 2,219,229 the fly-balls cause continuousrotation of the pilot valve plunger in its coacting flxed valve sleevethrough contact of the ball-arm fingers with a I disc portion h of theis so connected with compensation piston P that the piston is likewiserotated in its flxed cylinder. This eliminates the possibility ofbinding of either the valve plunger or said piston due to foreign matterin the hydraulic fluid and assures that the piot valve is free fromfriction and therefore free to respond to very slight changes in speed.The spring also allows relative'axial movement between the partsconnected thereby so that the valve is always free to respond promptlyto any change in centrifugal force acting on the fly-balls.

In operation, when the engine load is increased the resultant decreasein speed causes relative inward movement of the fly-balls; lowering ofthe pilot valve plunger; opening of the port E; admission of hydraulicfluid through duct 1 to the lower side of the power piston G, andincrease of fuel to the engine. The upward movement of the piston Gpumps fluid through duct 0; raising the receiving compensation piston P;compressing the spring Q and exerting an upward slight force on plunger;and the spring Q the plunger and receiving -The opposite end of the bore3 aavaaoc the pilot valve plunger suillcient to offset the temporaryoverbalance of speeder spring force relative to the centrifugal force onthe fly-balls, thus closing the port E. The port E is ordinarily closedsufflciently quickly to prevent overtravel of the power piston in thespeed correcting direction; and, as the engine returns to normal speed,the compression force of the spring Q is dissipated by reason of leakageof fluid from the duct 0 into the sump through the secondarycompensation leak-off aperture of the needle valve R.

The mechanism operates the same as described above for a decrease inload except that all the movements are reversedthe compensating spring Qbeing placed in tension by suction action of the compensation fluidsystem, and hydraulic fluid being flnally drawn from the sump into theduct 0 through the aperture of the needle valve R to relieve saidtension.

Speed adjusting or changing means is represented by the speeder plug Uat the upper end of the speeder spring M. Additional speed changingmeans would, of course, be provided, for example as in my Patent No.2,324,514 of which this application is a divison, or in other ways aswell known in the art. The fly-balls, speeder spring and adjustingmechanism for the latter constitute one example of speed weighing meansas referred to in the claims hereof and the pilot-valvecontrolledhydraulic servo-motor one example of speed regulating means as referredto.

Shown at the right, Figs. 1 and 2, and mounted as by screws (not shown)on the servo-motor block-T is a body I constituting a guide and workingchamber for. a hydraulically actuatable plunger or piston element 2movable transversely of the direction of movement of the power piston Gof the servo-motor. One end of the cylinder bore 2 in the body I for theplunger 2 is open to the servo-motor cylinder space lying above thepower piston G in various lowered positions of the power piston, asthrough a suitable passage 4 can be vented to the sump, as above thetrunk portion of the power piston, through a suitable passage 5. Theplunger 2 works in snug sliding contact with its cylinder bore, and hasa reduced portion 0 extending through a guiding openin 1 in theservo-motor block so that the reduced portion can abut the top face ofthe piston G as a latch, as illustrated in Fig. 1. A coil spring 8 liespartly in an axial cavity of the plunger 2 and reacts against an endwall 9 of the body I in a manner to force the latch portion 6 inwardlyinto latching or blocking abutment with the piston G. The plunger 2 islocated at whatever point along the servo-motor cylinder it is desiredto arrest the power piston in its initial power-input-increasing orupward stroke, and may, of course, be disposed at any desired pointcircumferentially of the power cylinder.

' open. Constant As shown the plunger 2 is arranged to stop the powerpiston at about half way between the limits of its stroke, or when thethrottle mechanism controlled by the power piston is half fluid from theacin the servo-motor cylinder block.

pressure will exist in the accumulator and connected ducts leading tothe top face of the power piston G. The power piston will of course bein its lowest possible position in the power cylinder as a result ofprevious shutting down of the engine. Upon restarting of the engine thefirst operation of the pilot valve H under speeder spring pressurethereon is to admit hydraulic pressure to the lower face J of the powerpiston, tending to cause the power piston to move to the full limit ofits power input increasing or upward stroke. The upward travel normallyis arrested only when the fiy-balls L have been moved by centrifugalforce to the vertical position in which shown or in position to closeboth ports E and I by adjustment of the pilot valve. Until nearly normalspeed on part of the engine is attained and the accumulator B ischarged, there is very little pressure at either working face of thepower piston. However there is enough to cause movement of the powerpiston to full throttle position in the absence of some means to preventor check such movement.

' The spring 8 of the plunger 2 has sufficient force to overcome theinitial pressure force on the left hand end of the plunger 2 during thefirst upward stroke of the power piston G.

Therefore the power piston is positively stopped intermediately of fullthrottle position when the upper face F of the power piston engages thelatch portion 6 of the plunger. As the engine picks up speed thepreponderance of pressure force continues to be exerted on the lowerface J of the power piston, the effective force increasing as theaccumulator becomes charged, wherefore the power piston continues tohold the latch in the position shown in Fig. 1 until normal or set speedon part of the engine has been attained. In other words friction on thelower side of the latch portion of the plunger 2.

prevents the increasing accumulator pressure from moving the latch towithdrawn position (Fig. 2) until centrifugal force on the fiy-ballsoverbalances the downward force of the speeder spring in holding thepilot valve plunger in depressed position (Port E open to duct I). Whenthe fiy-balls finally center the pilot valve plunger H a slightovertravel of the valve plunger opens the port K and the power piston Gmomentarily descends releasing the friction force on the latch portion 5of the plunger 2 and allowing constant pressure through the passage 4(acting also on the free inwardly exposed end of the latch portion 6) todrive the latch back out of the way of the power piston. Thereafter solong as the engine continues to run the plunger 2 remains in theposition shown in Fig. 2, and the power pistonis free to move upwardlypast the latch if required to do so in correcting speed followingincrease in load.

Since the plunger 2 remains in the position in which shown in Fig. 1until the engine attains speed and then moves quickly outwardly andstays in the position shown in Fig. 2, the plunger can be used tooperate an electric switch such as shown in Fig. 1 at IE or such asshownin Fig. 2 at 20. One element of each of such switch arrangements asshown can be carried on a pin l0 fixed to the plunger 2 centrallythereof and extending out of the body I through a suitable opening forthe pin which may be provided with an oil seal (not shown) in case thebody ,I is mounted on the outside of the governor case. If the plunger 2and its guide bore. are inside the case. as by forming the guide borevent ducts to the sump be required as at 5.

than

While the governor IS in operation, after starting, an opportunity forleakage of fluid outwardly along the pm In may be prevented by forming abevel i'ace II on the plunger 2 and a circular abrupt shoulder I? on theinterior of the body I for coaction therewith as a positive stop valveoperable as clearly shown in Fig. 2.

Referring to the switch and circuit arrangement at the right of Fig. lthe stationary element of the switch 15 is in a conductor l6 leading toa circuit breaker closing 0011 ll of a generator driven by the governedengine. With this arrangement since the switch contacts shown are closedonly when the engine has been fully started, the load is thrown onto thegenerator only when starting of the engine has been fully accomplished.

In Fig. 2 the line 2| represents an excitation forcing circuit of agenerator driven by the englue, and the switch 20 operates to close thecircuit, thus to force energization during acceleration of the engine,and to open the circuit and cease i'orcmg ehergization after the enginehas attained set speed.

In the claim hereof the expression movable within fixed extreme limitsas applied to the servo-motor is intended to indicate movement of thepiston G between the lower and upper ends or its cylinder, and a"complete cycle of operation" on part of the plunger element 2 indicates(a) the operation of the plunger portion 6 in arresting the piston G and(0) the operation thereof (hydraulically performed after mechamcalrelease) of moving clear of said piston as in order to open or close aswitch. The idle movement of the plunger back to original position afterthe governor stops functioning is not considered part of the operatingcycle.

Obviously a single plunger 2 can control more one electric switch or setof switches, for instance, one switch operating as shown in Fig. 1 andone switch operating as shown in Fig. 2.

Irrespective of the type of prime mover governed, the pilot valve andservo-motor would c0- operate as described to release and position thedevice 2, 6 to withdrawn position when full speed is reached; hence thedesirable operations as on a generator through use of the device 2, 6 asa switch control is available irrespective of whether or not latching ofthe nowerpiston temporarily in a particular position is needed.

I claim:

The combination with a hydraulic relay speed governor comprising a pilotvalve, speed responsive means controlling the pilot valve and a cylinderand piston constituting a hydraulic servomotor controlled by the valveand adapted to regulate the speed of a prime mover, of a device normallybiased into a position in the path of piston of the servo-motor andengageable by said piston in a manner to cause arrest of the pistonintermediately of its possible movement in powerinput-increasmgdirection during an initial stroke of the piston in said direction, andhydraulically operable means acting on said device to move the same to aposition clear of said piston consequent upon a partial return stroke ofthe servo-motor.

ALBERT m.

